1. Field of the Invention
The term dyslexia is used in the context of this disclosure to describe an individual who persistently reads inaccurately and one who has a lower than average recall or comprehension of the contents of what the individual has recently read. In some cases, the individuals are unable to count more than five symbols due to the level of visual confusion. This condition creates a great deal of frustration for such individuals and is frequently incorrectly perceived as a lack of intelligence. Accordingly, there is a continuing need for and interest in improved methods for the detection and treatment of this and other similar visual conditions.
2. Description of the Prior Art
The prior art discloses various different vision tests and screening methods. These tests typically define an individual's ability to read known letters or numbers of different sizes at various distances. The 100 year old Snellen test, which is an example of this type of test, reports an acuity such as 20/10 or 20/20, etc., reflecting the ratio of the distance at which the letters are recognized by a particular individual compared with the standard 20 feet.
Screening systems such as the one practiced by the testing machine known by the trademark TITMUS, and other similar systems, attempt to measure the ability of an individual to see gaps which are rotated in successive images viewed by the individual under test. Such tests detect abnormalities in vision, for instance astigmatism or lack of focus.
Still other screening systems, such as the one known under the trademark EYEDEX, causes the eyes of an individual to view the same object as two separate images, allowing the eye muscles to relax. From this test, the extent to which normal fusion of an image by the two eyes is a source of eye muscle stress to the individual can be determined.
Other known tests involve the selection of colored filters to enable an individual, while reading, to optimize their comfort level by selection of their preferred tint. This test is targeted particularly towards the so-called learning disabled individual.
Tests utilizing grids of graduated contrast printed lines have been employed to determine contrast sensitivity of individuals.
The test of the present invention described hereinafter was developed in response to the need to have a quantitative and portable on-site test of the individuals in their particular work environments. There are believed to be many more sources of visual work than presently defined, and accordingly, a need for a testing method which provides a quantitative measurement of visual capacity within a time frame, allowing for the comparison of difference optical environments and their impact on an individual.